Enhancement of flavor and aroma by microwave treatment

ABSTRACT

Botanical materials, such as tobacco, are treated with water and are then subjected to microwave energy to produce enhanced flavor and aroma perception. A solvent can be included with the water. The energy is sufficient only to enhance flavor and aroma perception, and not to expand the botanical material.

United States Patent 1 Heitkamp et a1.

1 Mar. 11, 1975 1 ENHANCEMENT OF FLAVOR AND AROMA BY MICROWAVE TREATMENT [75] Inventors: Norman D. Heitkamp,

Jeffersonville, Ind.; Steven L.

Merker; George E. Stungis, both of Louisville, Ky.

[73] Assignee: Brown & Williamson Tobacco Corporation, Louisville, Ky.

[22] Filed: June 6, 1972 [21] Appl. No.: 260,160

[52] US. Cl. ..13l/121,131/144,131/140 P [51] Int. Cl. A24b 03/12, A24b 15/04 [5 8] Field of Search 131/121, 140-140 P,

[56] References Cited UNITED STATES PATENTS 3,409.023 11/1968 de la Burde 131/121 2/1969 Hind 131/140 Primary Examiner Melvin D. Rein Attorney, Agent, or Firm-Finnegan, Henderson, Farabow & Garrett 57 ABSTRACT Botanical materials, such as tobacco, are treated with water and are then subjected to microwave energy to produce enhanced flavor and aroma perception. A solvent can be included with the water. The energy is sufficient only to enhance flavor and aroma perception, and not to expand the botanical material.

3 Claims, No Drawings BACKGROUND OF THE INVENTION The use of microwave energy for puffing tobacco has previously been disclosed. For example, US. Pat. No. 3,409,023 describes particular conditions for subjecting tobacco to microwave energy so as to puff the tobacco, particularly whole stems. In this process, puffing is accomplished by a particular alignment of the stems with regard to the microwave energy source.

In addition, U. S. Pat. No. 3,524,451 describes the puffing of tobacco by impregnating the tobacco with a volatile organic material and subsequently heating the impregnated tobacco so as to quickly release the volatile organic material so that the tobacco is expanded.

SUMMARY OF THE INVENTION In accordance with the present invention, it has unexpectedly been discovered that a combination of the processes referred to above, with some modifications, will lead to enhancement of flavor and aroma in botanical materials, particularly tobacco, through carrying of these flavor and aroma constituents from the interior of the botanical particle to the surface. In particular, the botanical is treated with water and is then subjected to microwave energy. While not wishing to be bound by theory, this appears to result in an internal distillation, the water being heated by the microwave energy and acting to drive the flavor and aroma constituents to the surface of the tobacco or other botanical material.

An inert, volatile, organic solvent can be combined with the water in treating the botanical material. In

such case, the organic material will act as a carrier for the flavor and aroma constituents and, when heated by the internally distilled water, will aid in carrying the flavor and aroma constituents to the surface.

The microwave energy is supplied at a sufficient level to carry the flavor and aroma constituents to the surface without expansion of the botanical material. The power to accomplish this is less than 0.25 kilowatt per pound of contained water.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the present invention, botanical materials, such as tobacco, are treated to attain a moisture level of from 5 to 75%, preferably from 30 to 55%. Such moisturizing treatments are well known in the art and any of the well known treatments can be employed.

Subsequent to treating the botanical material to the particular moisture level, or concurrently with this treatment, the tobacco or other botanical material, may have a quantity of a volatile, inert, organic material impregnated into it. It is not important that the botanical be totally saturated with the organic material, but, when used, there should be at least an amount sufficient to solubilize the flavor and aroma constituents of tobacco.

Organic solvents which are useful according to the process of the present invention, as they solubilize the flavor and aroma constituents just described and as they are volatile enough to be driven from the tobacco particle under the action of the water heated by microwave energy include hydrocarbons, ethers, halohydrocarbons, alcohols, esters and ketones.

Among the specific materials which can be so employed are methylene chloride, diethyl ether, isopentane, hexane, petroleum ethers and 1,2-dichloro- 1,1 ,2,2-tetrafluoroethane.

Following impregnation of the botanical material with water or with water and an inert, volatile organic solvent, the botanical is subjected to microwave energy. Any means by which the botanical material can be subjected to microwave energy can be employed.

0 For example, the treated botanical material can be placed on a moving belt which passes through a microwave field. Similarly, the treated botanical material can be conveyed by a moving air stream through a microwave field. Other means, well known in the art can also be employed.

The microwave energy used is generally at those frequencies used for industrial, scientific and medical uses. For example, these frequencies are generally at 915 or 2,450 megacycles. Only sufficient energy need be imparted to the treated botanical material to heat the water contained within the botanical material so as to carry the flavor and aroma constituents to the surface. When a solvent is employed, the water need be heated only to such a degree as to volatilize the solvent. The power per unit mass is less than 0.25 kilowatt per pound of water contained in the botanical material. Preferably, the power level is from 0.05 to 0.25 kilowatt per pound of contained water.

The temperature of treatment with microwave energy is not important, solong as the moisture content of the botanical can be maintained and the organic solvent is not prematurely volatilized.

In order that those skilled in the art may be better enabled to carry out the process of the present invention, the following examples are given. These examples should be considered as illustrative, only, and not as limiting in any way the full scope of the invention, as covered in the appended claims.

Example 1 Both the stem and lamina of tea were treated to obtain a water level of approximately'30%. A second treatment followed to provide a methylene chloride level of 1%. The tea was then irradiated with microwave energy at a frequency of 2,450 megacycles and a power of 2,500 watts for about 5 seconds to provide a power level of approximately 0.20 kilowatt per pound of water. The flavor enhancement of the tea particles, following this treatment, was confirmed by taste. Example 2 V Stems and lamina from a tobacco plant were treated to a moisture level of 45%. The thus treated tobacco was irradiated with microwave energy at a frequency of 2,450 megacycles and a power of 2,500 watts for about 5 seconds, toprovide a power level of approximately 0.15 kilowatt per pound of contained water. The resulting tobacco was formed into cigarettes which were smoked by a panel of trained smokers who confirmed that the flavor and aroma characteristics of the resulting cigarettes were superior tothose of similar cigarettes made with untreated tobacco.

Example 3 Tobacco stems and lamina were treated to obtain a moisture level of 37%. They were subsequently treated to achieve a methylene chloride content of based upon the weight of the pre-moistened tobacco. Subsequently, the tobacco was irradiated with microwave energy at 2,450 megacycles, 2,500 watts for 10 seconds,

to provide a power level of approximately 0.25 kilowatt per pound of contained water. Such a treatment did not result in expansion of the tobacco particles, but such expansion was incipient. The resulting tobacco was formed into cigarettes which were evaluated by a panel of trained smokers who confirmed that the flavor and aroma of the cigarettes were enhanced compared with cigarettes formed from the same tobacco, but not subjected to the process of the present invention. Example 4 .A quantity of pipe tobacco was treated to obtain a moisture level of-l9 to and the tobacco was then impregnated with l% ethanol. The tobacco was then treated in the same manner as in Example 1 and trained pipe smokers, upon using the tobacco, perceived enhanced flavor and aroma.

A process for enhancement of flavor and aroma, by forced migration of flavor and aroma constituents, for botanical materials has thus been described.

We claim:

l. A process for enhancing the flavor and aroma characteristics of botanical materials comprising:

a. treating said botanical materials with a combination of water and an inert nontoxic, volatile, organic solvent in which the flavor and aroma generating materials are soluble to obtain a moisture level of from 5 to 755; and b. subjecting the botanical material to microwave energy at a frequency of at least 915 mc and a power level of from 0.05 to 0.25 kilowatt per pound of contained water for a period of time and at a.distance such that said solvent is substantially volatilized and the flavor and aroma of said botanical material are improved without substantially expanding said material. 2. The process of claim 1 wherein the botanical material is tobacco.

3. The process of claim 1 wherein said frequency is between 915 to 2,450 mc. 

1. A PROCESS FOR ENHANCING THE FLAVOR AND AROMA CHARACTERISTICS OF BOTANICAL MATERIALS COMPRISING: A. TREATING SAID BOTANICAL MATERIALS WITH A COMBINATION OF WATER AND AN INERT NONTOXIC, VOLATILE, ORGANIC SOLVENT IN WHICH THE FLAVOR AND AROMA GENERATING MATERIALS ARE SOLUBLE TO OBTAIN A MOISTURE LEVEL OF FROM 5 TO 755; AND B. SUBJECTING THE BOTANICAL MATERIAL TO MICROWAVE ENERGY AT A FREQUENCY OF AT LEAST 915 MC AND A POWER LEVEL OF FROM 0.05 TO 0.25 KILOWATT PER POUND OF CONTAINED WATER FOR A PERIOD OF TIME AND AT A DISTANCE SUCH THAT SAID SOLVENT IS SUBSTANTIALLY VOLATILIZED AND THE FLAVOR AND AROMA OF SAID BOTANICAL MATERIAL ARE IMPROVED WITHOUT SUBSTANTIALLY EXPANDING SAID MATERIAL.
 1. A process for enhancing the flavor and aroma characteristics of botanical materials comprising: a. treating said botanical materials with a combination of water and an inert nontoxic, volatile, organic solvent in which the flavor and aroma generating materials are soluble to obtain a moisture level of from 5 to 75%; and b. subjecting the botanical material to microwave energy at a frequency of at least 915 mc and a power level of from 0.05 to 0.25 kilowatt per pound of contained water for a period of time and at a distance such that said solvent is substantially volatilized and the flavor and aroma of said botanical material are improved without substantially expanding said material.
 2. The process of claim 1 wherein the botanical material is tobacco. 